Originally, medical triage was a process deployed during wartime or disasters by which a nurse or other medical professional personally performed an initial assessment of patients to group them into one of three categories: those too ill to benefit from immediate medical care, those well enough to survive without immediate care, and those who could benefit from immediate care. In situations in which immediate medical care was a scarce resource, triage methodology helped ensure that such care would be allocated rationally, for maximum aggregate benefit.
In a broader sense, medical triage is a process for sorting people with medical complaints into groups based on the likelihood of them benefiting from particular levels of medical treatment. For example, most hospital emergency rooms utilize some kind of triage methodology to determine the priority in which patients receive care. The methodology can also include a decision-making strategy for deciding whether a nurse is able to dispense an adequate level of care or a physician is required for a higher level of care. Much of this is done in person, using medical assessments such as blood pressure, pulse, skin color, and general observations of the patient to supplement what the patient describes about his or her condition. The staff then applies hospital triage rules based on that information to determine treatment priority and a level of care, typically aiding those with the most serious conditions first.
Such medical triage systems exist to ensure that an appropriate level of care is dispensed to all individuals, by evaluating the significance of their self-reported or observed symptoms and matching them with a particular level of care. Accurate triaging means that the patient's medical concerns receive a suitable level of medical attention—neither substantially more nor substantially less than what he or she needs.
Triage systems can also ensure that the dispensation of care is more economically efficient. In this age of ballooning medical costs, a medical triage system can mean that whoever ultimately pays for the medical services (e.g., government, companies or individuals) does not pay for an unnecessary level of treatment. For example, if someone with a minor injury is accurately triaged, an appropriate level of care can be determined, while expensive services, such as ambulance transport and emergency department care, can be avoided, if unnecessary.
Some triage systems are focused on controlling and limiting utilization of medical services (i.e., gate keeping). These triage systems are operated by or paid for by insurance companies and/or third party administrators responsible for general health care costs. The system guides callers to medical generalists, rather than to more costly specialists, except when a specialist is necessary. These systems will also direct referrals to in-network (i.e., discounted) medical providers, steering callers away from out-of-network (i.e., non-discounted) providers.
The spread of telecommunications means that some types of medical triage can be employed by persons who are not on-site with the patient. Advances in triage methods have enabled persons without extensive medical training to conduct some types of triage, so long as they are trained in the triage methods. A common form of triage that is conducted telephonically and by non-medical professionals with specialized training is that used by 911 Emergency Medical System (EMS) dispatching services. However, these services generally operate under the assumption that some emergency medical response will be sent to all callers. The dispatcher typically determines the level of response (e.g., whether basic or advanced life support is dispatched, which ambulance or other responder is closest to the caller, and which caller 105 gets priority when there are multiple simultaneous calls). EMS dispatchers also provide pre-arrival instructions, guiding callers in simple life saving techniques to help stabilize patients until emergency personnel arrive.
Medical providers, including clinic and hospital departments, may also utilize a triage service for screening purposes. For example, many expectant mothers and parents call obstetricians' and pediatricians' offices with a variety of medical complaints, concerns and questions. A triage service can play a role in determining which patients need to see a physician and which do not. Many clinics use their own staff for this triage service, but other clinics out-source to call centers. Similarly, many doctors' offices, clinics and hospital departments use call centers to answer their telephones on weekends and after business hours. In addition to handling scheduling and message services, these call centers often use a level of triage to determine which calls warrant paging an on-call doctor.
Most triage calls begin with a nurse recording the medical condition or injury as stated by the caller, along with the caller's demographic information. This is followed by questioning by the nurse and a short health history. The nurse will assess the symptoms, provide information on seeking care and improving symptoms, and refer the caller to a physician, if necessary. Documentation of the call can be the final part of the triage process.
Many of the existing services described above provide a triage service in which nurses apply a variation of the free-form triage, answering callers' medical questions using the nurse's own expertise or general guidelines. While sample protocols, risk factors and other information can be provided, these systems do not establish a broadly applicable and consistent decision-making process. Nurses are left to formulate their own questions and direct their own investigations. Even with general guidelines such a system can be rife with inconsistencies and other limitations. Each nurse can have his or her own particular predilections and can steer the inquiry in a direction not warranted by a fuller understanding of a particular patient's condition or optimal practices obtained by methodical study of prior triage cases. The nurse can miss critical points as a result of sloppiness or lack of knowledge and can, as a result, direct more treatment or less treatment than is appropriate. It can be impossible to ensure consistency and quality control with this kind of system.